`AsyncSwiftUIImageView`: always request image `onAppear`
`AsyncSwiftUIImageView`: always request image `onAppear`

This ensures that if everything is ready, a request is sent.
If the data hasn't changed since the last request, this is a no-op because `AsyncImageLoader` uses `skipRepeats`.

NachoSoto/AsyncImageView,NachoSoto/AsyncImageView,NachoSoto/AsyncImageView